The present invention relates to the technical sector of remote control of inflation and deflation of a capacity from a source of gaseous fluid under relative pressure, and it more particularly relates to the remote control of the inflation pressure of the tires of automobiles and all terrain machines with wheels for industrial, agricultural, civilian or military uses,
In the preferred domains of application above, it is known that it is sometimes useful to be able to remotely control the inflation pressure of the tires of a vehicle, so that it is possible to adapt the supporting ability of these tires as a function of the state of the ground on which the vehicle is moving.
This is the case in particular for all-terrain vehicles which must be able to advance under the best conditions over hard, pebbled, loose ground surfaces capable of alternating, without the driver being obliged to stop in order to manually modify the inflation pressure of the different tires.
It is also the case for agricultural machines such as tractors, towed elements, self-propelled harvesters which, in addition to the problems of advancing in loose ground, must limit the packing of the ground and the formation of ruts in the fields, and handle transports on the road without deterioration of the tires.
These applications are only given as examples because in numerous domains, it also proves useful or even necessary to be able to adapt at a distance the inflation pressure of a certain capacity for containment of a gaseous fluid under relative pressure.
In order to solve this problem above, prior art offers some solutions.
Thus, French patent 9105351 describes a pneumatic valve which has a membrane which moves a cup which has a hole and a seat for a flap, a mobile apparatus of two flaps in opposition, respectively for inflation and outflow, which is sensitive to the position of the membrane, an elastic component which acts on the apparatus in order to maintain the inflation flap in closed position on the seat connected to the membrane, some elastic means associated with the membrane for maintaining the outflow flap in closed position on a seat arranged in the base of the valve, a stop which limits the course of travel of the outfit in opening of the outflow valve. The control of the deflation is ensured by a low positive pressure.
Such a valve partly corresponds to the desired function, but has limitations of use. In effect, the positive control pressure imposes a limit on the minimum pressures which are measurable and prohibits its use for the lowest pressures used on very loose terrain and in particular for agricultural work. Furthermore, its manufacturing which requires a large number of parts is delicate and expensive.
Another known proposal of prior art concerns a controlled pneumatic valve which is described in patent EP-0 296 017, valve which has a membrane connected to a flap automatically controlled and maintained between a half-body and a grooved ring which, with the half-body, delimits a control chamber, and with the grooved ring, delimits an outflow chamber, the latter communicating with a hole which opens in the capacity, the control chamber being subjected to a circuit of pressure-vacuum through a hose, said automatically controlled flap pushing the membrane to close the bore and coaxially incorporating a check valve. Such a valve gives satisfaction but has a certain number of disadvantages.
For example, in case of off-center mounting on the wheel, which is ordinarily imposed by the configuration of the hub, the centrifugal force acts on the ball of the check valve and interferes with closing of this valve at high speed, causing gradual deflation of the tire.
This valve is furthermore difficult to use for agricultural type vehicles with very negative pressures because of the lack of sealing of the check valve, the bearing forces which depend on the pressure held in the capacity not being sufficient to complete the contact between the ball and the seat of the flap.
The present invention aims to solve the problems mentioned previously by providing a simple and inexpensive device which is completely reliable and which can be used in a wide range of pressure and speed.